Analog-to-digital converters (A/D converters, ADCs) are widely used in a plurality of different electronic circuit applications, such as microcontrollers. ADCs serve to convert an analog input signal into a discrete or digital output signal representing the analog input signal. Due to inevitable variations in the manufacturing process of ADCs, ADCs produced in the same process may have different parameters, such as offset or gain. Thus, calibration of an ADC is required before use.
ADCs can be calibrated using special testing or calibration equipment. Such testing equipment, however, is expensive and requires calibration at the end of the fabrication process in the manufacturing plant. On-chip calibration, which means calibration of the ADC only using the circuit where it is employed, or a recalibration some time after the manufacturing process is not possible.
There is, therefore a need for providing a signal processing circuit that allows for on-chip calibration of an ADC.